膀胱抗菌机制—粘膜抗菌蛋白初步研究

本文报道以１％乙酸冲洗雌性Ｗｉｓｔａｒ大鼠膀胱和雌性新西兰白兔膀胱，分别获得其膀胱酸溶性提取物。ＡＵ－ＰＡＧＥ分析表明，两种膀胱粘膜酸溶性提取物都有十余条主蛋白带，而不含常见的杀菌物质溶菌酶和防御素样分子。琼脂糖弥散法杀菌试验显示，两种膀胱粘膜酸溶性提取物对致病性大肠杆菌ＭＬ－３５ｐ耐药株都有杀菌活性。进一步采用电泳凝胶琼脂糖弥散法杀菌试验分析，结果表明大鼠膀胱粘膜酸溶性提取物中有两条蛋白带具明显的杀菌活性，我们称这两条蛋白带为ＲａｔＢＰ－１和ＲａｔＢＰ－２。而兔膀胱粘膜酸溶性提取物的杀菌活性亦与两条被称为ＲａｂＢＰ－１和ＲａｂＢＰ－２的蛋白带相关。本文首次提示，在膀胱粘膜内存在抗菌蛋白，可能是膀胱粘膜杀菌作用的分子基础。

URINARY BLADDER ANTIBACTERIAL MECHANISMS:PRELIMINARY STUDY ON MUCOSAL ANTIBACTERIAL PROTEINS

The acid-soluble extracts of rat and rabbit bladder mucosal surface were obtained by washing the bladders offemale Wistar rats and New Zeal rabbits with 1?etic acid in the presence of protease inhibitors.AU-PAGEanalysis indicated that both of the extracts had more than 10 main protein bands.The antibiotic peptides,e. g. lysozyrne and defensin- like molecules , were not found in these acid-soluble extracts.When tested for antibacterialactivity by using ultrasensitive radial diffusion assay , both of the extracts effectively killed E. coli ML-35P. Thebactericidal activity of the acid-soluble extracts was further analysed by gel overlay technique.The results showedthat two main protein bands , rat bladder protein 1(Rat BP-1) and rat bladder protein 2(Rat Bp-2), were potentlyantibacterial against E. coli ML-35P. The antibacterial activity of rabbit acid-soluble extract was also relevant totwo protein bands ,rabbit bladder protein 1(Rab BP-1 ) and rabbit bladder protein 2(Rab Bp- 2)The Rat BP-1 andRat Bp-2 accounted for 5% and 2% of the total rat acid-soluble extract proteins ,and Rab BP-1 and Rab Bp-22.5%and 1.2%,respectively. These results suggest that the antibacterial proteins in the bladder mucosa may bethe molecualr base of antibacterial mechanisms.